WOI, IA 10-09-06 New Weapon in Meth Battle Authorities have a new weapon in the fight against meth that could have national and international implications. Two Iowa State University researchers discovered that by adding calcium nitrate to a popular meth ingredient, anhydrous ammonia, makes the substance useless to meth cooks. The finding was the result of a six year project and more than a million dollars. Iowa's Drug Czar says 93-percent of Iowa's meth labs use anhydrous ammonia. The Secretary of Agriculture says the calcium nitrate will not have any negative impact on the environment or farm equipment. It will be used on a voluntary basis and cost an estimated 24 dollars per injection per tank.